The latest version of the free, open-source email manager, Thunderbird, is in the wild—in an alpha release rough enough around the edges to earn the code-name "Shredder." It doesn't have all the features promised for Thunderbird 3 yet, but you can see where it's headed. I installed "Shredder" in Windows XP, and I'll show you what's there, and explain what's coming soon, after the jump.

Note: In case it wasn't clear from the introduction, Thunderbird 3 Alpha 1 is very rough indeed—the developers have all but promised you'll get crashes, bugs, and feature conflict. You could, if you wanted, install the alpha to a different folder than your current T-bird setup (be sure to choose "Custom installation") and back up your current Thunderbird profile ( more on that here), but "Shredder" might still give you a headache. If that's cool with you, you can grab the first alpha build at Mozilla Messaging, the spin-off Mozilla group now in charge of the email app.

On to the good stuff. Installation was pretty familiar territory in Windows, and I was relieved to see that Gina's guide to Using Thunderbird with Gmail IMAP is still valid. Once your account is set up, you land at a pretty familiar sight, at least in Windows:

Gmail's IMAP support roll-out this week had nerds all atwitter about the possibility of…
Read more Read more

What Windows users won't see is that the OS X version of Thunderbird 3 uses Macs' native Cocoa styling for a more integrated look (a Wired preview has a rough screenshot). And on every system, Thunderbird is using the Gecko 1.9 rendering engine, the same back-end that saves memory and moves a bit swifter in Firefox 3.

The most obvious wholly-new feature in Thunderbird 3 is an option for opening new messages in tabs. In "Shredder," you have to do this with a right-click on messages in your inbox, but we'll assume this can be a default option, or a keyboard shortcut, in the final release.

The other new feature that might give Thunderbird power-users a smile is a Firefox 3-like add-ons manager, which lets you search for Thunderbird-specific extensions and install them from within one window, rather than hunting on Mozilla's site, right-click saving, hitting "Install" and so forth. You can also manage plugins like Flash and multimedia handlers from this window.

Mac users get another long-awaited feature with Thunderbird 3's ability to integrate with the native OS X Address Book. This rough feature is disabled by default, but developer Bryan Clark posts a work-around for the adventurous.

A few more features look promising in Thunderbird 3, but I wasn't able to grab photo evidence (or the evidence just wasn't very exciting visually). They include:

Better integration with Lightning, the nifty calendar manager that can be a bit wonky as an add-on in Thunderbird 2.

A chance for more powerful third-party extensions through a new API dubbed STEELE.

Better search functionality, with a promise of fewer false positive matches and some multi-lingual awareness.

Extensive code cleanup throughout the app (well, when they release the final, we'll assume), and improved crash and bug-reporting tools

What vital features do you see missing in Thunderbird 3? If you've ventured into the alpha, what do you like so far, or cringe at? Share your thoughts in the comments.